The present invention relates to a non-invasive system for sub-epidermal epilation and permanent hair removal from sub-epidermal tissue (Sub-Epidermal-System "SES"), and particularly to an improved system and method for hair removal utilizing high frequency induced cellular coagulation within the hair follicle. Unwanted hair is a common dermatological and cosmetic problem, and can be caused by heredity, malignancy, or endocrinologic diseases such as hypertrichosis (i.e., excess hair), hirsutism (i.e., androgen-influenced hair) as well as prior attempts at follicular hair removal that only further stimulates hair growth.
Growth of each hair is originated by germinativa fibroblast cells in the basal layer of the epidermis. The hair grows both outwards and inwards during its growth cycle, and the follicle develops as an encapsulating pouch extending beyond the epidermis and down several millimeters in depth to the dermis and in the rare case bridges on the subcutaneous fat. Hair remains attached to the base of the follicle, where a capillary network develops to provide nourishment. During the anagenic growth phase, hair matrix cells divide rapidly and migrate upwards to form the shaft. A subsequent catagenic phase is marked by cessation of mitosis, and the reabsorption of the lower part of the follicle. Capillary nourishment is greatly reduced during this phase. In this or the final telogenic (resting) phase, the hair falls out and a new hair may replace it in a new growth cycle. At any particular time, approximately 10% of scalp hairs will be in telogenic mode.
The growth cycle varies with anatomical location from as little as three (3) months for facial hair to as much as seven (7) years on the scalp. However, hair in high friction and pubic areas may be retained by the body as protection and may not shed at all.
The hair follicle consists of a mixture of germinativa cells and melanocytes. Sebaceous cells empty into the follicle, providing a lipid-rich environment. The follicle may range between 0.1 and 0.001 mm in diameter and may extend to 4 mm in depth. The average hair diameter within the follicle is 0.125 mm. Hair itself is generated as an accumulation of dead (keratinized) cells. Structurally it consists of two (2) or three (3) discrete layers. The outer cuticle layer consists of a single layer of overlapping flap, acting as a protective barrier. In turn, an inner cortex layer may consist of any pigment which may be present (pigment may also reside in melanocytes lining the follicle). Pigment may exist as two melanin forms. Eumelanin is responsible for brown/black coloration and pheomelanin is responsible for red/blonde coloration. Larger, fully developed terminal hairs also contain a core known as the medulla.
In the lower follicular region, a bulge is formed where the arrector pili muscle contacts the follicle. This muscle controls movement and orientation of the hair and may, under appropriate stimuli, render the hair vertical with respect to the skin surface. The bulge area has one of the fastest rates of cell division found in mammals, stimulated by growth factors from the lower papilla area.
Finally, there is the bulb at the base of the hair follicle. Generally, the bulb area is the area in which the hair is initially generated and further attached to the body and nourished via predisposed capillaries.
While the hair follicle and hair contained therein function at several different levels, excess body hair does present a cosmetic problem for females and males. As a consequence, many individuals undergo hair removal treatments. Hair can be temporally removed using a number of techniques including wax removal, depilatory creams, lasers, and of course, shaving. Alternatively, in past electrolysis techniques hair may have been temporarily removed. These past applications of electrolysis techniques involved the intention of inserting a needle into a hair follicle capable of conducting electrical current, lye decomposition or both. The insertion and application of electrical current in turn has resulted in cellular destruction (scarring) that is often painful, with inefficient results, that in turn is time consuming because of the lack of specific needle placement in the subepidermal tissue, depths of insertion, heat application and duration of application.
Electrolysis is used by in excess of 1 million women in the United States. It is well known that in past and present techniques hair is temporarily remove by electrolysis wherein a needle/probe is inserted through the epidermis, hair follicle and dermis into the sub-cutaneous tissue, and beyond, well into the patient and well beyond the hair follicle. Then high voltage is applied as to a needle/probe generating heat when conducted in the body, thus destroying the surrounding cells, intended or otherwise. Such misdirected cellular destruction can result in dimpling and scaring. The primary problems with the prior techniques is in scarring and the creation of considerable pain caused by improper insertion of the needle/probe and application of high heat into the tissue of the patient.
Hair removal through electrolysis has been performed for many years, and through electrolysis, patients have been temporarily able to selectively remove hair from certain body areas. Ordinarily, this hair removal process is carried out by inserting a needle/probe into an individual's individual hair follicle and beyond. This obviously can be a very painful ordeal and also is unduly time consuming, because only one hair is removed at a time and may necessitate several applications, over the course of years, without permanency. In some techniques patients are grounded by having the patient hold a ground terminal in his/her hand. This results in electricity passing through a large area of the patient's body, which in some cases can cause efficiency and conductivity problems and can further destroy necessary tissue. In past electrolysis techniques, repeat treatment sessions over years are necessary to remove all unwanted hairs from a particular area, all without permanency and causing cellular damage.
In the early stages of electrolysis, there was much confusion and speculation as to why it worked. Some investigators, for example, postulated that the hair follicle was "electrocuted". Later, it was hypothesized that it works because of electrolytic action that gives rise to chemical decomposition in the hair follicle, but needless to say there was adverse chemical decomposition in surrounding cells.
Past electrolysis techniques, save the teachings herein, are still not well understood. Within each hair follicle, there is a solution of salt water that provides the chemicals for the electrolysis process to work. Specifically, subjecting the salt water solution to an electric current results in the salt (NaCl) and the water (H2O) breaking into their constituent chemical elements. This application is referred to as electrolysis, and the subsequent rearrangement of the basic elements of salt and water is referred to as ionization. One of the new compounds that is formed as a result of the ionization is sodium hydroxide (NaOH). The sodium hydroxide produced is highly caustic to the hair follicle and causes the follicle to die through a decomposition of the hair root, and inadvertent decomposition of the surrounding cellular structures. In some instances, by chance or luck, the general epithelium of the follicle is killed, rendering the follicle unable to ever produce more hair so long as the deadening reduces the capillary blood flow to the follicle, thus eliminating the possibility of cellular regeneration. After the hair follicle has been treated in this manner (decomposed), the hair can be removed by extraction without guarantee of permanency.
As shown in the patent to Cole (U.S. Pat. No. 5,026,369, hereinafter the "'369 patent"), the method of electrolysis may utilize an electrode solution as a medium for conducting current to the tissue and salt water content of the hair follicles. The electrode solution enhances conductivity because the skin surface and the hairs themselves are less effective conductors of electricity than is the electrode solution.
In the past, two techniques have been primarily used in the electrolysis field. Galvanic (DC) current can be passed down a fine needle/probe or needles inserted into the follicle. Tissue in the area of the electrical charge is converted from local tissue saline to sodium hydroxide, which destroys the follicle. Furthermore, the thermolysis technique utilizes an AC current to directly heat and thereby destroy the papilla. Some clinicians utilize a combination approach of these two electrolysis techniques. Some electrolysis techniques treat a single follicle at a time, in a painful procedure which can require localization or even anesthesia. Needle/probes are re-used in this unsanitary, non-permanent, time consuming, multiple treatment technique.
As pointed out above, hair removal through a conventional electrolysis technique, where the skin is actually perforated and then penetrated with a tapered, one-piece, inflexible needle/probe, is very painful. Therefore, a need exists for a painless and more efficient method for removing unwanted hair. Furthermore, most present day electrologists are self taught or have minimal formal training and therefore have minimal awareness of the finite demands associated with electrolysis and therefore may tend to harm rather than help the patient. Previous attempts to address the problems inherent with current and past techniques resulted in attempts to develop non-invasive electrolysis without substantive success.
In 1993, Thermotrex Corporation was assigned two Hair Removal Device and Method patents (U.S. Pat. Nos. 5,226,907 and 5,425,728) based on the use of an externally applied chromophore to enhance local absorption of laser light. In these patents, a topically applied substance is said to penetrate to the full depth of the root of the follicle. The substances cited include permanent hair dyes, suspensions of carbon particles and photosensitizing compounds. A subsequent application of laser light is said to induce a photothermal reaction which destroys the follicle and a surrounding tissue area.
The compounds cited by Thermotrex in their patents will probably demonstrate follicular selectivity. Many other topical compounds, and some systemic compounds, exist as candidates. Liposomal or lipophilic compounds may favor the lipid rich environment. Alternatively, solvents such as ethanol may be used to de-lipidize or re-organize the sebum, and thereby open the follicular passageways. Deposition of hydrophilic drugs may be facilitated by the action of wetting agents such as sodium lauryl sulfate, which may promote the creation of an emulsion. Particle size clearly plays a role in terms of ability to penetrate through narrow epidermal structures and along the follicular duct. The approach cited in this invention may work, although its practice involves the use of expensive laser equipment. Further, the use of topical compounds prolongs treatment and raises potential risk without guarantee of success.
A second technique has been studied and reported by Drs. Melanie Grossman and Rox Anderson whereby single high energy normal mode Ruby laser pulses are applied to the skin in the absence of an externally applied chromophore. No issued patent has been awarded covering this work. In this method, the optical target is the melanin within the inner cortex layer and the pigment-bearing melanocytes lining the follicle. High frequencies of up to 60 J/sq.cm. are utilized in large spotsizes, with short pulse widths of the order of 150 mu sec and a wavelength of 694 nm. This technique employs a number of natural phenomena to enhance effect on the deep follicular component. A large applied spotsize and high fluence allow for maximum depth of penetration. Concurrent cooling spares bulk tissue structures from the edema and general damage which can result from the use of frequencies of this magnitude. Intimate index-matched contact of the custom handpiece with the tissue minimizes reflection loss. However, the short pulse widths used in this approach are unlikely to efficiently transfer heat to the entire follicular structure. The Ruby laser is not readily capable of the requisite millisecond-domain pulses necessary to effect a true thermal mechanism.
A third approach, utilizing the Q-Switched Ruby laser, was disclosed by Nardo Zaias in his 1990 U.S. Pat. No. 5,059,192. This patent cited the use of a Q-Switched Ruby laser at 694 nm, with 3-8 mm spotsize and around 8 J/sq.cm. Pulse width was in the range 30-40 nanoseconds. Light energy administered in such a short pulse width will be well retained in the melanocytes lining the follicle. This approach will provide potential for melanocyte destruction and perhaps permanent depigmentation or destruction of the hair, but likely will not kill the follicle itself, since the pulse width is insufficiently long to conduct heat away from the targeted melanin granules.
In 1967, U.S. Pat. No. 3,538,919 was filed by R. Meyer. Meyer cited the placement of a fiber directly into the follicle into which a total of 30-40 J/cm&lt;2&gt; of light was subsequently launched. This fluence was administered over a period of 1-2 milliseconds, preferably by a normal mode Ruby or Nd:YAG laser. Use of a 50 um fiber was cited. This fiber diameter would theoretically fit into a 100 urn follicle containing a 50 um hair, but with difficulty.
In 1970, Richard Harte filed U.S. Pat. No. 3,693,623, which also cited the placement of a fiber directly into each follicle to be destroyed. The light source here was a xenon lamp, which applied up to 3 mJ to each follicle, in an interval of less than 3 msec. This technique is a difficult process to administer.
In 1973, Carol Block was issued U.S. Pat. No. 3,834,391, which similarly addressed the placement of a fiber at the follicular entrance. Light source was unspecified. This patent introduced the concept of the use of mineral oil, said to facilitate light conduction, presumably by index matching. No additional chromophore was added.
In 1981, H. Weissman filed an application, later granted as U.S. Pat. No. 4,388,924. This cited the devitalization of hair by the specific destruction of the papillary blood supply. A narrow beam from an Argon laser was directed onto the tissue. This light was said to be absorbed by the papillary plexus, causing heating and coagulation. Multiple 20-30 millisecond exposures from a 0.5-2.5 Watt beam were cited. The hair was subsequently tweezed from its follicle. This method calls for the selective destruction of the papillary plexus and is unlikely to be practical using a narrow beam Argon laser, with its limited penetration depth capabilities, since this supply resides at several millimeter depth and is shielded by the overlying follicular structure. Indeed, no vascular specific lasers are likely to exhibit adequate dermal penetration.
In 1984, A. Sutton filed a patent, later granted as U.S. Pat. No. 4,617,926. This provided for the use of a fiber without a core, into which an individual hair slides by 2-3 mm, completing the wave guiding action. Different probes were cited, and about 1 Joule of energy launched into the fiber, from an unspecified laser source. In an alternative embodiment, the fiber is sharpened and inserted directly into the follicle. This technique is likely to result in rapid probe destruction. In Sutton it is alleged that the hair can be used as a optical waveguide to conduct the optical energy to the base of the follicle without damaging the surrounding tissues. No explanation is given as to how hair, which is not transparent nor hollow, can function as a waveguide, so that the operability of the Sutton proposal is questionable. Other proposals have involved probes which must be inserted much like electrolysis needle/probes to deliver the optical energy directly to the hair root. See Block U.S. Pat. No. 3,834,391 issued Sep. 10, 1974 and Mayer, U.S. Pat. No. 3,538,919 issued Nov. 10, 1970.
The delivery of the energy may be through the use of a hand piece having means for scanning a beam in order to locate the entrance to the hair root structure at the skin. Other automatic and semiautomatic systems for locating a housing carrying the laser beam and its optical system may be used. The U.S. patent to Weissman referenced above shows one such system.
Optical beams for hair removal have been suggested in several patents. Optical-based methods, such as the use of laser light, have also been used for hair removal. U.S. Pat. No. 4,388,924, for example, describes irradiation of individual hair follicles using a laser; in this method, heating of the hair's root section causes coagulation in local blood vessels, resulting in removal of the follicle. Related techniques, such as those described in U.S. Pat. No. 5,226,907, involve removal of the follicle by first applying a light-absorbing substance to the region of interest, and then irradiating the substance to heat and remove the follicle. The optical energy is not used to ablate the hair and its root structure as provided for by the present invention, in that beam delivery system is not an optical system which shapes and restricts the beam to a subcutaneous ablation cavity, that is a volume where ablation can occur and is restricted.
In U.S. Pat. No. 5,059,192, issued to Zaias and in a patent issued Jul. 13, 1993 to Tankovich, U.S. Pat. No. 5,226,907, reliance is placed on selective photo thermolysis, that is the selective absorption of the incident laser radiation by the melanin in the follicle to cause localized heating.
Like past electrolysis techniques, lasers also have proven limitedly effective in the permanent removal of hair, without regard to unnecessary scaring and cellular destruction. Previous attempts to address the problems inherent with temporary, un-safe, invasive, discomfiting hair removal have been ineffective and misdirected. The present invention provides for and teaches non-invasive, safe, non-damaging, permanent hair removal with optimal effectiveness and with minimal or no patient discomfort.